It is known to construct inserters for infusion sets which hides and protects the insertion needle before insertion and which retracts the insertion needle after penetration of the patients skin and thereafter hides and protects the insertion needle.
Such a device is known from EP 1.762.259. The inserter according to this document comprises a needle hub comprising an insertion needle and two spring units assuring automatic insertion and automatic retraction of the insertion needle. Although the design of the device is compact and user friendly the mechanism is relatively complex and provided with parts which have to move in relation to each other.
The present invention provides both protection of the insertion needle before insertion and after retraction and at the same time the inserter device is of a very simple construction which makes it both non-expensive to produce and reliable.
Another device is known from US 2004/0116865 A1. This document relates to a needle insertion device comprising a housing with a mounting surface adapted for application to the skin of a subject where the mounting surface defines a general plane and has a needle aperture formed therein. A needle comprises a distal pointed end adapted to penetrate the skin of the subject, the pointed end being arranged within the housing in respect of the general plane. The mounting surface surrounding the needle aperture is moveable a first and a second position, in the first position the pointed end of the needle is arranged within the housing and in the second position the pointed end of the needle projects through the needle aperture as the skin portion corresponding to the intended injection site of the needle is pulled against the needle. According to this device the injection needle is stationary relative to the housing and the bi-stable member moves the skin in stead of the injection needle.
WO 2001/076684 discloses a disposable infusion device which device delivers an infusible liquid to a patient. The infusion device (10) is used to deliver predetermined amounts of infusible liquid, such as liquid medicines, insulin, etc., to an injection site on the patient or user in a controlled manner. A cannula (28) may be subcutaneously inserted by an injection needle (30). The injection needle (30) and the cannula (28) are supported and protected by a collapsible member (46) prior to injection. The collapsible member (46) provides a stable base such that the cannula (28) is not easily moved around under the skin of the body. The injection needle is withdrawn leaving the cannula (28) in place. An inserter as described in U.S. Pat. No. 5,851,197 may be used when inserting the needle (30) and the cannula or alternatively the needle (30) might be pushed manually into the skin by the user. WO 2001/076684 does not relate to or describe an inserter device; the collapsible member (46) does not provide energy for insertion of the needle (30) and/or the cannula (28), the collapsible member (46) only provides a stable base for the cannula (28).
US 2002/022798 discloses a fluid delivery device which is capable of achieving a constant and precise flow rate for medication kept in an internal reservoir. An annular flexible membrane (34) is attached to the inner surface of a top cover (12) and forms an internal fluid reservoir (36) wherefrom medication is delivered to the patient. To activate the fluid delivery device the user manually presses down on the top cover (12, 212) until a cannula (48, 216) penetrates the skin of the patient. At this position a Belleville spring (40, 226) pushes against the internal reservoir and provides for a constant flow of medication to the patient. The Belleville spring does not provide energy for insertion of the cannula/insertion needle.